Seems many onsite got their training from www.thecraft.com founded by Chris Kyle (USN), a recently famous sniper.
Orders before Oath? Where is their HONOR?
http://www.freerepublic.com/focus/f-news/3147140/posts
An un-sourced report of 3 guys wearing skull ball caps is hardly enough to call out a particular company. Anyone can buy a hat from their site, and there are a lot of hats with skulls that look similar.